The control of the adhesion of surfaces is an important field of material sciences. Adhesion forces between surfaces can be produced in different ways. A distinction is drawn here between mechanical bonding, such as clamping and anchoring (“hook and loop fastener”), chemical bonding, such as covalent bonds or charges, and physical bonding, such as Van der Waals forces. It is precisely the physical bonding, i.e. the Van der Waals forces, that is important for many technical and biological systems.
Here, in the case of the adhesion of solid bodies, the elasticity of the bodies or of the surfaces plays an important role for the adhesive and repulsive forces that are produced. In order to describe these forces, use is frequently made of the Johnson-Kendall-Roberts model (JKR) (K. L. Johnson, K. Kendall, A. D. Roberts (1971) Surface energy and contact of elastic solid. Proceedings of the Royal Society A. 324, 301-313.). In this model, for example, the adhesion of a sphere to a flat surface was investigated. For example, the attraction of the sphere by Van der Waals forces leads to deformation in the direct vicinity of the surface, depending on the elasticity of the sphere, and also to deformation of the surface in this region. This deformation is limited by the rigidity of the sphere and of the surface. An equilibrium is formed between deformation and adhesion force.
This model has been developed further through numerous studies and also used already to simulate rough surfaces (K. L. Johnson (1995) The adhesion of two elastic bodies with slightly wavy surfaces. International Journal of Solids and Structures, 32, 423-430; C. Y. Hui, Y. Y. Lin, J. M. Baney, E. J. Kramer (2001) The mechanics of contact and adhesion of periodically rough surfaces. Journal of Polymer Science B, Polymer Physics, 39, 1195-1214; G. Carbone, L. Mangialardi (2004) Adhesion and friction of an elastic half-space in contact with a slightly wavy rigid surface. Journal of Mechanics and Physics of Solids, 52, 1267-1287; P. R. Guduru (2007) Detachment of a rigid solid from an elastic wavy surface: Theory. Journal of the Mechanics and Physics of Solids, 55, 445-472.).
A still unsolved problem here is the control of the adhesion forces between two solid bodies.
The object of the invention is to specify a combination of a first and a second device. The combination is to permit the adhesion forces between the two devices to be controlled. In addition, the invention is to specify a device which permits control of the adhesion, and also a corresponding method.